More than 400 gallons of mineral oil leak in Straits of Mackinac

At least 400 gallons of mineral oil have leaked into the Straits of Mackinac.

American Transmission Company operates power lines that deliver electricity between the Upper and Lower Peninsulas. The company called the U.S. Coast Guard on Monday night to inform them of a leak of dielectric fluid, which is used to insulate the electrical lines under the Straits.

Company spokesperson Jackie Olson said the company discovered the leak early Monday morning.

“The cables contain a mineral-based fluid for insulation and it was determined sometime in the early morning that there was indications of a leak,” Olson said.

Olson said hazardous weather including ice cover has prevented the company from investigating the damage.

“As a result, those two cables that were damage cannot be repaired and have been rendered permanently inoperable and we are determining the condition of other cables in the straits,” Olson said.

Olson said it is likely residual fluid from the lines will continue to leak.

There have been no power outages related to the line failure.

Federal, state and local authorities are responding to the pollution.

“Safety of the public and our responders is our top priority," said Coast Guard Captain Marko Broz in a statement on Tuesday afternoon. "We are further committed to protecting the environment and ensuring a proactive response.”